The short version of heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-09-16 and is reviewed periodically as new material appears.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Travis Charles Colyer (born 24 August 1991) is a former professional Australian rules footballer who played for the Essendon Football Club and Fremantle Football Club in the Australian Football League (AFL).
== Use in diagnostic tests == Fecal elastase is an enzyme originally thought to be pancreatic elastase 1 (CELA1), but this was discovered to be an error, and it is actually likely be CELA3B. Fecal elastase is not degraded in intestinal transit, so that its concentration in feces reflects exocrine pancreatic function. In inflammation of the pancreas, fecal elastase is released into the bloodstream. Thus the quantification of fecal elastase in serum allows diagnosis or exclusion of acute pancreatitis. Main indications:
The government dissolved the National Assembly in its first days and the cabinet ruled by ordinance-laws signed by the tsar, invoking Article 47 of the Tarnovo Constitution. On 14 June political parties and trade unions were banned and their property was nationalised. Counties and municipalities were clustered, their self-government abolished and replaced by government-appointed officials. Stricter qualification criteria for teachers were introduced, dozens of schools were closed and over 2,000 teachers were left unemployed. A campaign was organized to replace the traditional names of many villages in the country with Bulgarian ones. Strict censorship was introduced and many printed publications were banned. In order to increase state revenues and subsidize agriculture, the government established state monopolies in the grain, alcohol, and tobacco trades, severely disrupting activity in these sectors. Up to 40% of debts that were difficult to service after the Great Depression were cancelled, the rest were rescheduled, and enforcement measures were limited. Several distressed private banks were consolidated and reactivated with state capital to form the Bulgarian Credit Bank. The two large state-owned banks were also merged into the Bulgarian Agricultural and Cooperative Bank. A Public Assistance Service was established under the Ministry of the Interior, financed by a special tax, and free treatment of the poor in public hospitals was introduced.
Sources: en.wikipedia.org
=== 11 April === Russia launched a massive air attack on cities and energy infrastructure across Ukraine, killing five people in Mykolaiv and destroying the Trypilska thermal power plant in Ukrainka, Kyiv Oblast. Two storage facilities belonging to the state gas firm Naftogaz were also targeted. President Zelenskyy said that the power plant was destroyed after air defenses ran out of missiles after intercepting seven Russian missiles, resulting in four other missiles hitting the facility. The FSB claimed to have thwarted an attempted landing by Ukrainian special forces in occupied Kherson Oblast, inflicting casualties and capturing a commando. Ukrainian authorities ordered the evacuation of families with children from 47 communities in Kharkiv Oblast near the border with Russia due to Russian attacks. Ukrainian military commanders convinced the Verkhovna Rada to drop a clause from a bill on mobilization of Ukrainian military personnel that allowed soldiers who had fought for 36 months a chance to be discharged. Citing the ongoing Russian offensive, the officers claimed that the clause would "weaken the defence forces". The bill was passed later in the day after over four thousand amendments were submitted since its introduction in February 2024. It must now be signed into law by Zelenskyy.
The white shark is the sole living species in the genus Carcharodon and is one of five living species of the family Lamnidae. The other four members of this family are the mako sharks, porbeagle, and salmon shark. The family belongs to the Lamniformes, the order of mackerel sharks. The white shark first appears in the fossil record in the Pacific basin around 6–5 mya, between the late Miocene and early Pliocene. Like all sharks, the white shark's skeleton is made primarily of soft cartilage that does not preserve well. As a result, the overwhelming majority of fossils are teeth. Nevertheless, paleontologists have traced the emergence of the white shark and its immediate ancestry to a large extinct shark known as Carcharodon hastalis. This species had teeth similar to the modern white shark's, except for the cutting edges, which lacked serrations. C. hastalis occupied a similar position in the food web to modern white sharks and was probably mostly fish-eating, with some marine mammals in its diet, though its lack of serrations made it a less efficient predator of them. Around 8–6 mya, a Pacific population of C. hastalis evolved into C. hubbelli. This divergent lineage was characterized by a gradual development of serrations over the next few million years. Teeth from the same time period may exhibit significant variation in shape and their serrations, which may be indicative of persistent interbreeding with C. hastalis for at least some time. White sharks descended from C.
Agmatine, also known as 4-aminobutyl-guanidine, was discovered in 1910 by Albrecht Kossel. It is a chemical substance which is naturally created from the amino acid arginine. Agmatine has been shown to exert modulatory action at multiple molecular targets, notably: neurotransmitter systems, ion channels, nitric oxide (NO) synthesis, and polyamine metabolism and this provides bases for further research into potential pharmacological applications.
Sources: en.wikipedia.org
== Biological function == G-CSF is produced by endothelium, macrophages, and a number of other immune cells. The natural human glycoprotein exists in two forms, a 174- and 177-amino-acid-long protein of molecular weight 19,600 grams per mole. The more-abundant and more-active 174-amino acid form has been used in the development of pharmaceutical products by recombinant DNA (rDNA) technology.
=== Suppression of the pro-Alid groups === Mu'awiya died in 680 and was succeeded by his son Yazid I. Mu'awiya's designation of his son was an unprecedented act and shocked many in the Muslim community, particularly the Arab nobility of Kufa. They long sympathized with Caliph Ali, Mu'awiya's former rival, and Ali's family. One of Ali's sons, Husayn dispatched his cousin Muslim ibn Aqil to Kufa to set the stage for Husayn's accession to the caliphate. Ibn Aqil garnered significant support and was hosted by a prominent pro-Alid nobleman. Ubayd Allah became aware of Ibn Aqil's activities, prompting the latter to launch a premature assault against the governor. Ubayd Allah was holed up in his palace, but thirty men from his shurta (security forces) fended off Ibn Aqil's partisans, while he persuaded many Kufan noblemen to back him against Ibn Aqil, who was abandoned by his supporters and slain on 10 September 680. Husayn had already been en route to Kufa from Medina when he received news of Ibn Aqil's execution. Ubayd Allah was prepared for Husayn's arrival and sent troops to intercept him. They prevented Husayn and his small retinue from reaching the watered areas of the province. The two sides negotiated for weeks, but Ubayd Allah refused Husayn entry into Kufa or return to Arabia while Husayn refused to recognize Yazid's caliphate. In the end, a short battle was fought at Karbala on 10 October 680, in which Husayn and nearly all of his partisans were slain.
Some of the functions of tears include lubricating the eyes (basal tears), removing irritants (reflex tears), and also aiding the immune system. Tears also occur as a part of the body's natural pain response. Emotional secretion of tears may serve a biological function by excreting stress-inducing hormones built up through times of emotional distress. Tears have symbolic significance among humans.
== Chemistry == While the molecular weight of nicotinamide riboside is 255.25 g/mol, that of its chloride salt is 290.70 g/mol. As such, 100 mg of nicotinamide riboside chloride provides 88 mg of nicotinamide riboside.
Sources: en.wikipedia.org
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.